Gas ejection device with a silencer feature

ABSTRACT

An ejection system comprises a flat fishtail nozzle opening into a flat fairing open at both ends to form therewith a static pump or ejector. The nozzle is subdivided into a succession of elementary nozzles producing a laminar jet of hot gases, and the fairing is likewise subdivided into as many separate juxtaposed elementary ducts as there are elementary nozzles. Each such elementary nozzle is associated with a respective elementary duct to form therewith an elementary static pump.

United States Patent [151 3,685,612 Bertin [451 Aug. 22, 1972 [54] GAS EJECTION DEVICE WITH A 2,396,208 3/ 1946 Serre et al ..l8 1/33 HC SILENCER FEATURE 3,527,318 9/1970 Duthion et al ..l8 1/60 [72] Inventor: Jean Henri Bertin, Neuilly-Sur- FOREIGN PATENTS OR APPLICATIONS Seme France 657 569 1/1929 F 181/51 rance Assignee= Berlin & Cie Boite Postale, Plaisiz, 725,510 2/1932 France ..l8l/60 France 859,758 9/1940- France ..l8l/6O 22 M 3 1971 865,279 2/1941 France ..l8l/60 1 441,932 3/1927 Germany ..l8l/5l [21] Appl. No.: 139,402

Primary Examiner-Robert S. Ward, Jr. [30] Foreign Application Priority-Data Attomey Alfred Bremer May 4, 1970 France 7016227 [57] ABSTRACT U-S An ejection System Comprises a flat nozzle 181/33HD 239/265 opening into a flat fairing open at both ends to form [51] Int Cl B64! 33/66 o 1/12 F01 n & therewith a static pump or ejector. The nozzle is sub- [58] Fie'ld 181760 72 43 51 33 HQ divided into a succession of elementary nozzles 181/33 50 5 7 producing a laminar jet of hot gases, and the fairing is likewise subdivided into as many separate juxtaposed elementary ducts as there are elementary nozzles. Each such elementary nozzle is associated with a [56] References Clted respective elementary duct to form therewith an ele- UNITED STATES PATENTS memary Static P p- 1,357,079 10/1920 Patch ..l8l/43 9 Chain, 6 Drawing Figures 8 9 7 S ,1, i 1 a 31 7 2 a, 4 Y MH EJ- PATENTEU \972 3.685.612

saw 1 OF 5 PATENTEDAUBZZ m2 3.685612 SHEET 3 [1F 5 GAS EJECTION DEVICE WITH A SILENCER FEATURE This invention relates to a flat fishtail-shaped nozzle for exhausting hot gases such as the hot exhaust gases of a turbojet or other jet engine. Fishtail nozzles are familiar and are described in French Pat. Nos. 1,164,692 and 1,207,634 and in Guienne et al. US. Pat. No. 3,212,700; these disclosures also indicate that such nozzles can, with advantage, be combined with a flat fairing open at both ends to form a static pump and that the nozzles have a silencer effect.

It is an object of this invention to improve such devices so as to improve their performance, inter alia as regards the static pump and the silencer features, but without incurring the thrust losses associated with the conventional sound-damping systems for jet nozzles whether or not the latter are of the static pump kind, for static pumps on their own have little effect on jet noise.

In the ejection device according to this invention, the fishtail nozzle which in association with a flat fairing has a static pump effect is subdivided into a sequence of elementary nozzles producing a laminar stream of hot gases, and the fairing is subdivided into as many separate juxtaposed elementary ducts as there are elementary nozzles, each elementary nozzle being associated with an elementary duct to form an elementary static pump.

Preferably, the elementary nozzles are cruciform and the elementary ducts are of rectangular cross-section, to improve the static-pump and silencer effects. To further improve silencing, the flat fairing is divided into compartments by sound-damping partitions which serve to bound the elementary ducts.

Flaps for controlling the fairing exit cross-section can be fitted very readily and efiectively to a construction of this kind which is subdivided into juxtaposed elementary static pump; the flaps, which are adjustable, are articulated transversely of the spread of the jet or stream and can be short lengthwise of the flow.

The device according to this invention is of use not only in aircraft propulsion but also in surface vehicle propulsion, e.g. ground effect machines; it also has possibilities in other fields, e.g. fog dispersal, snowand frost-clearing aerosolizing.

The following description, taken together with the accompanying exemplary non-limitative drawings, will show clearly how the invention can be carried into practice.

In the drawings:

FIG. 1 is a view in side elevation of a jet engine having an ejection device according to this invention, the fuselage and the staticpump fairing being assumed to be transparent to clarify the drawing;

FIG. 2 is a plan view in similar conditions;

FIGS. 3 and 4 are perspective views to a larger scale, and with parts broken away, of the rear terminal part, and

FIGS. 5 and 6 are views similar to FIGS. 3 and 4 of two constructional variants.

Referring to the drawings, a turbojet engine 1 has an air inlet 2 which intakes air through a sound-insulated tube 3 which has a front inlet 4 and forms a forward extension of a pod 5. An exhaust nozzle 6 for the hot gases has a flat fishtail shape and terminates in an outlet portion 7 opening into fairing 9 which is in shape substantially oblong and which comprises a solid sheetmetal outer casing 10 and an inner sheet-metal perforate casing or wall 11 which serves to bound a convergent-divergent duct, the nozzle outlet plane 7 being disposed at the throat of the convergent-divergent duct. The space between the casings or walls 10 and 11 can be either filled with a sound insulant, such as mineral wool, or left empty, in which event the space acts as a resonator, the diameter of the apertures in the wall 11 being determined in dependence upon the predominant frequency of the exhaust gas noise.

According to this invention, the nozzle outlet crosssection 7 takes the form of a sequence of cruciform elements 8 from which the hot gases issue in the form of thin lamina at right angles to one another. Fairing 9 is subdivided into compartments by sound-insulated longitudinal partitions 20 so that each cruciform element 8 is disposed separately in a substantially rectangular cross-section elementary duct 12. The ducts 12 make up a group of ejectors or static pumps whose leading edge, represented by a line A-A, is a series of fresh air inlets 15 positioned upstream of the outlet planes of the cruciform elements 8, the fresh air being intaken as indicated by arrows f. The leading edge A-A can either be straight or have a pattern such as shown by way of example in FIGS. 2 and 3. The shaded zone represents the volume affected by the hot engine exhaust gases; the total delivery through the ducts 12 is the result of the exhaust gases mixing with the fresh air f and is represented by arrows F.

Combining thin lamina of hot gases with partitioned elementary ducts and with sound insulation of the partitions of the latter ducts leads to an appreciable reduction in the noise level; there is also an improved staticpump effect.

The design of the fractionated ejection system just described allows incorporation of flaps disposed in the fairing outlet plane and serving for directional control of the gas velocity vector. This idea is shown in FIG. 5; flaps l3l3 are disposed at the trailing edge of the fairing 9 and can pivot about transverse pivots orspindles l414. The flaps 1313, which are paired, are in this embodiment disposed in extension of the fairing top and bottom surfaces. The fiaps13, which are stiffened and balanced by elements 16, are disposed downstream of the partitions 20 and can be operated to pivot around their pivot 14 so as to control the thrust vector direction of the engine 1.

In the variant shown in FIG. 6, the fresh-air inlet line A-A is perpendicular to the engine axis so that the front cross-section is annular, the elementary fresh-air inlets 15 being disposed in the same plane as one another in a ring around the nozzle 6. Two series of individual flaps 17 are disposed in the rear portion of the fairing 9, between the insulated partitions 20 and in the prolongation of the fairing top and bottom surfaces.

Of course, instead of the articulated-partition type flaps 13 of FIG. 5 and 17 of FIG. 6, similar devices of known kind can be used, such as shutters, deflectors or obstacles, to achieve a directional effect or even jet reversal such as provided by clam-shell devices.

lclaim:

1. An ejection device comprising a source of hot gases, a flat fishtail nozzle supplied with hot gas from said source and subdivided into a succession of elementary nozzles designed to produce a laminar hot gaseous jet, and a flat fairing open at both ends and accommodating therein said fishtail nozzle, said fairing being likewise to said fishtail nozzle subdivided into as many separate juxtaposed elementary ducts as there are elementary nozzles, each elementary nozzle and respective elementary duct forming together an elementary static pump.

2. A device according to claim 1 wherein the elementary nozzles are cruciform and eject the hot gases in thin lamina at right angles to one another.

3. A device according to claim 1 wherein the elementary ducts are of rectangular cross-section.

4. A device according to claim 1 wherein the fairing is divided into compartments by sound-damping partitions which serve to bound the elementary ducts.

5. A device according to claim 1 wherein the fairing is double-walled and comprises a continuous outer wall and a perforate inner wall bounding a convergentdivergent channel, the fishtail nozzle extending to the throat of the channel.

6. A device according to claim 5 wherein the space between the two fairing walls is filled with sound-damping material.

7. A device according to claim 5 wherein the space between the two fairing walls is empty and acts as a resonator, the diameter of the apertures in the perforate wall being determined in dependence upon the predominant frequency of exhaust gas noise.

8. A device according to claim 1 further comprising control flaps fitted at the exit of the fairing and articulated transversely of the spread of the stream.

9. A device according to claim 8 wherein the flaps are subdivided into elementary flaps each associated with one of the elementary ducts of the fairing.

UNITED STATES PATENT OFFICE CERTIFICATE 'OF CORRECTION Patent No. 3, 685, 612 Dated August 22, 1972 Inventor(s) JEAN HENRI BERTIN It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Title page, Assignee address, "Boite Postale, Plaisiz, should read BoTte Postale No. 3, Plaisir Signed and sealed this 13th day of November 1973.

(SEAL) Attest 2 EDWARD NLPLETCHERJR. RENE D. TEGTMEYER Attesting Officer Acting Commissioner of Patents FORM PC1-1050 (10-69) USCOMM-DC 50376-P69 fi' US. GOVERNMENT PRINTING OFFICE: QII 0Ji6-S3|4 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 685, 612 Dated August 22, 1972 Inventor(s) JEAN I'IENRI BERTIN It is certified that error appears 1T1v the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Title page, Assignee address, "Boite 1 051 2316; Plaisiz, should read Boite Postale N0. 3, Plaisir Signed and sealed this 13th day of November 1973.

(SEAL) Attest:

EDWARD NLFLETCHERJR. RENE D. TEGTMEYER Attesting Officer T Acting Commissioner of Patents F ORM PQ-1050 (10-69) v uscoMM-oc 60376-P69 a US. GOVERNMENT PRINTING OFFICE 2 9'9 0-356-33l 

1. An ejection device comprising a source of hot gases, a flat fishtail nozzle supplied with hot gas from said source and subdivided into a succession of elementary nozzles designed to produce a laminar hot gaseous jet, and a flat fairing opEn at both ends and accommodating therein said fishtail nozzle, said fairing being likewise to said fishtail nozzle subdivided into as many separate juxtaposed elementary ducts as there are elementary nozzles, each elementary nozzle and respective elementary duct forming together an elementary static pump.
 2. A device according to claim 1 wherein the elementary nozzles are cruciform and eject the hot gases in thin lamina at right angles to one another.
 3. A device according to claim 1 wherein the elementary ducts are of rectangular cross-section.
 4. A device according to claim 1 wherein the fairing is divided into compartments by sound-damping partitions which serve to bound the elementary ducts.
 5. A device according to claim 1 wherein the fairing is double-walled and comprises a continuous outer wall and a perforate inner wall bounding a convergent-divergent channel, the fishtail nozzle extending to the throat of the channel.
 6. A device according to claim 5 wherein the space between the two fairing walls is filled with sound-damping material.
 7. A device according to claim 5 wherein the space between the two fairing walls is empty and acts as a resonator, the diameter of the apertures in the perforate wall being determined in dependence upon the predominant frequency of exhaust gas noise.
 8. A device according to claim 1 further comprising control flaps fitted at the exit of the fairing and articulated transversely of the spread of the stream.
 9. A device according to claim 8 wherein the flaps are subdivided into elementary flaps each associated with one of the elementary ducts of the fairing. 